Dimethyltin esters

ABSTRACT

Dimethyltin derivatives of lower toxicity are prepared by reducing the amount of trimethyltin impurity.

United States Patent Weisfeld et al. *Dec. 9, 1975 DIMETHYLTIN ESTERS [52] US. Cl 260/45.75 S; 252/406 75 Inventors: Lewis w Id x 51 lm. c|.- C086 6/00 1 Robert C z ;:Z;::: 6' [58] Field of Search 260/45.75 K, 45.75 s; 252/406 [73] Assignee: Cincinnati Milacron Chemicals Inc.,

Readmg Ohm [56] References Cited Notice: The portion of the term of this UNITED STATES PATENTS gzg g g'z gaigzg June 1992 2,832,751 4/[958 Weinberg et al. 260/4575 [22] Filed: Apr. 9, 1974 OTHER PUBLICATIONS [2H Appl No 459372 J. Applied Chemistry 4 June 1954, pp. 3 l4 to 3l8.

Related US. Application Data Primary Examiner-V Hoke [63] Continuation-impart of Ser. Nos. l77,5l6, Sept. 2, Attorney Agent or Flrm cushman' Darby &

1971, and Ser. No. 317,228, Dec. 21, 1972, Pat. No. Cushma" 3,810,868, and Ser. No. 435,264, Jan. 2i, i974, Pat. No. 3,887,519. {57] ABSTRACT Foreign Applimfion Priority Data Dimethyltin derivatives of lower toxicity are prepared June 7, 1973 Germany 2329039 by reducing the amount of trimethyltin impurity.

49 Claims, 4 Drawing Figures DIMETHYLTIN ESTERS The present application is a continuation-in-part of application Ser. No. 177,516, filed Sept. 2, 1971; of application Ser. No. 317,228, filed Dec. 21, 1972 now Pat. No. 3,810,868; and of application Ser. No. 435,264, filed Jan. 21, 1974 now US. Pat. No. 3,887,519.

The present invention relates to dimethyltin compounds of reduced toxicity and their use as stabilizers for halogen containing resins.

According to the present invention there are prepared dimethyltin compounds having the formula:

cu, R,

wherein R, and R are S(CH ),,COOR -S(Cl-l,)- COOR'OCO(Cl-l ),,S-, OR SR O- COCH=CHCOOR OCOR chlorine or R and R together are either S or O. In the formula R R R 'and R are hydrocarbon or divalent sulfur (thioether) substituted hydrocarbon or oxygen (ether) substituted bydrocarbon or oxygen (ether) substituted hydrocarbon, e.g., alkyl, cycloalkyl, alkenyl, benzyl, tolyl, phenyl, of up to 20 carbon atoms, preferably 4 to 12 carbon atoms, n is an integer of 1 to 3 and R is a divalent hydrocarbon (alkylene), chlorine substituted divalent hydrocarbon, divalent sulfur (thioether) or oxygen (other substituted hydrocarbon of 2 to 6 carbon atoms).

Typical compounds of this type are shown in Mack US. Pat. No. 2,684,973, Lan'gkammerer US. Pat. No. 2,253,128, Quattlebaum US. Pat. No. 2,307,157, beistner US. Pat. No. 2,641,596, Leistner US. Pat. No. 2,726,254, Best US. Pat. No. 2,731,484, Weinberg US. Pat. No. 2,746,946, Mack US. Pat. No. 2,809,956,- Weinberg US. Pat. No. 2,832,750 and Weisfeld US. Pat. No. 3,640,950. The entire disclosure of Weisfeld, both Mack patents, Langkammerer, Quattlebaum, both Leistner patents, Best and Weinberg patents is hereby incorporated by reference.

Among the compounds of reduced toxicity prepared according to the invention are dimethyltin dichloride, dimethyltin oxide, dimethyltin sulfide, dimethyltin bis- (isooctyl thioglycolat dimethyltin bis(isooctyl-S-mercaptopropionate, dimethyltin bis (2-ethylhexylthioglycolate), dimethyltin bis (2'-ethylhexyl-3-mercaptopropionate), dimethyltin bis (isooctyl 4-mercaptobutyrats dimethyltin bis (n-octyl thioglycolate), dimethyltin bis(n-acty1-3-mercaptoprdpionate), dimethyltin bis (methyl thioglycolate), dimethytin bis (methyl 3-mercaptopropionate), dimethyltin bis (methyl 4 mercaptobutyrate), dimethyltin bis (ethyl thioglycolate dimethyltin bis(propyl 3-thiopropionate), dimethyltin bis(butyl thioglycolate), dimethyltin bis(butyl 3-thiopropionate), dimethyltin bis (butyl-4-thi'obutyrate), dimethyltin bis (isooctyl 2-thiopropionate), dimethyltin bis (decyl thioglycolate), dimethyltin bis (dodecyl thioglycolate), dimethyltin bis (dodecyl 3-thiopropionate), dimethyltin bis (dodecyl 4-thiobutyrate), dimethyltin bis (octadecyl thioglycolate), dimethyltin bis (octadecyl 3-thiopropionate), dimethyltin bis (octadecyl 4- thiobutyrate dimethyltin bis (cicosanyl thioglycolate), dimethyltin bis( cicousanyl -3-thiopropionate), di-

methyltin bis (cyclopentyl thioglycolate), dimethyltin bis (cyclohexyl thioglycolate), dimethyltin bis (cyclohexyl-3-thiopropionate), dimethyltin bis (benzyl thioglycolate), dimethyltin bis(benzy1-3-thipropionate), dimethyltin bis (phenyl thioglycolate), dimethyltin bis(p-tolyl-B-thiopropionate), dimethyltin bis (allyl thioglycolate), dimethyltin bis (allyl-3-thiopropionate dimethyltin bis (allyl-4-thiobutyrate), dimethyltin bis(- crotyl thioglycolate), dimethyltin bis( oleyl thioglycolat dimethyltin bis (oleyl-B-thiopropionate), dimethyltin bis (oleyl-4-thiobutyrate), dimethyltin octyl thioglycolate decyl thioglycolate, dimethyltin bis(methallyl thioglycolate), dimethyltin bis (methallyl-3thiopropionate), dimethyltin bis(dodecenyl thioglycolate, dimethyltin dimethoxide, dimethyltin dibutoxide, dimethyltin diisooctoxide, dimethyltin didodecoxide, dimethyltin dioctadecoxide,'dimethyltin dimethyl mercaptide, dimethyltin diethyl mercaptide, dimethyltin dipropyl mercaptide, dimethyltin dibutylmercaptide, dimethyltin diisooctylmercaptide, dimethyltin di(Z-ethylhexyl mercaptide), dimethyltin dioctyl mercaptide, dimethyltin didodecyl mercaptide, dimethyltin dioctodecyl mercaptide, dimethyltin dieicosanyl mercaptide, dimethyltin diallyl mercaptide, dimethyltin dioleyl mercaptide, dimethyltin dicyclohexyl mercaptide, dimethyltin diphenyl mercaptide, dimethyltin dibenzyl mercaptide, dimethyltin diacetate, dimethyltin dipropionate, dimethyltin dibutyrate, dimethyltin divalerate, dimethyltin dihexanoate, dimethyltin dioctanoate, dimethyltin didecanoate, dimethyltin dilaurate, dimethyltin dimyristate, dimethyltin dipalmitate, dimethyltin distearate, dimethyltin dieicosanoate, dimethyltin methoxy acetate, dimethyltin methoxy oleyl maleate, dimethyltin butoxy octadecyl maleate, dimethyltin ethoxy methyl maleate, dimethyltin propoxy isooctyl malcate, dimethyltin di( methylmaleate), dimethyltin di (ethylmaleate), dimethyltin di (propylmaleate), dimethyltin di (butylmaleate), dimethyltin di(octylmalcate), dimethyltin di (isooctyl maleate), dimethyltin di (Z-ethylhexyl maleate), dimethyltin di(benzyl maleate), dimethyltin di (dodecyl maleate), dimethyltin di (octadecyl maleate), dimethyltin di (phenyl maleate) dimethyltin di (oleyl maleate), dimethyltin di (allyl maleate), dimethyltin diacrylate, dimethyltin dimethacrylate, dimethyltin dicrotonate, dimethyltin ethylene bis thioglycolate (the reaction product of dimethyltin dichloride with ethylene bis thioglycolate of the formula HSCH,COOCH,CH COCCH,SH), dimethyltin propylene bis (thioglycolate), dimethyltin trimethylene bis(- thioglycolate), dimethyltin hexamethylene bis(thioglycolate), dimethyltin ethylene bis (3-thiopropionate), dimethyltin diethyleneglycol bis (thioglycolate), dimethyltin thiodiglycol bis (thioglycolate). The products containing divalent groups such as -S(CH,)- COOROCO (CH ),,S preferably are prepared using chain stoppers such as S(CH ),,COOR in proportions to give small polymers.

Other compounds within formula 1 include dimethyltin bis (2-chloroethyl thioglycolate), dimethyltin bis (3- chloropropyl thioglycolate), dimethyltin bis (2-chl oroethyl-3-thiopropionate) dimethyltin bis (methoxyethyl thioglycolate), dimethyltin bis (methoxypropyl thioglycolate), dimethyltin bis (ethoxyethyl-S-thiopropionate), dimethyltin bis(butoxyethyl thioglycolate), dimethyltin bis (ethoxyethoxy ethyl thioglycolate), dimethyltin bis (methylthioethyl thioglycolate), dimethyltin bis (methylthioethyl mercaptide).

While many organotin compounds have been proposed as stabilizers for polyvinyl chloride (PVC), e.g., see Weinberg U.S. Pat. No. 2,648,650, Leistner U.S. Pat. No. 2,641,596, Kauder U.S. Pat. No. 3,222,317 and Hechenbleikner U.S. Pat. No. 3,396,185, from their inception the organotin stabilizers employed commercially have all been butyltin products except for the use of octyltin stabilizers for food contact articles. The most important organotin stabilizer is dibutyltin bis- (isooctyl thioglycolate) available commercially under the trademark ADVASTAB TM-l80. While many tin stabilizer patents since about 1950 have included an R group of l to 8 or more carbon atoms attached to the tin, only butyls and to a lesser extent octyls have in fact been used commercially. The propyl tins are known to have an obnoxious odor, ethyl tin compounds are toxic. Methyltin compounds have been considered water soluble, insufi'lciently compatible with polyvinyl chloride and to have toxicity problems, particularly as skin irri- 12111115.

Historically, the largest producer of organotin compounds in the United States is M & T Chemicals, Inc. In a Symposium on Polyvinylchloride Stabilization Status and Trends" presented at the 160th American Chemical Society meeting in Chicago, Illinois in the fall of 1970 a nine-page paper was presented by A. J. Ejk and W. A. Larken of M&T Chemicals, Inc. on Organotin Stabilization". This article states on page 2 that tetravalent butyltin compounds are of prime importance as organotin stabilizers and points out defects in all other alkyltin compounds. Thus it states that methyltin compounds are soluble in water. Among the more useful organotin stabilizers is listed dibutyltin S,S' bis (isooctyl mercapto acetate). The article further points out that organotin compounds are frequently used in synergestic mixtures which include various mercaptides and carboxylates as well as zinc soaps (e.g. zinc stearate), phosphites (e.g. triphenyl phosphite), epoxies (e.g. epozidized soya bean oil), glycerides, UV absorbers and/or antioxidants. Ejk et al classify tin stabilizers for polyvinyl chloride (PVC) as normal (tin content 16-18%) high (tin content 23-25%) and low (tin content 7-8%) efficiency stabilizers. Normal are preferred, high efficiency stabilizers presenting a dispersibility problem because of their low use. It will be observed that dimethyltin bis (isooctyl thioglycolate) has a tin content of 21.4% and dimethyltin bis (isooctyl mercaptiopropionate) has a tin content of 20.4%.

Ejk et al. also show that di (n-octyl) tin S,S' bis (isooctyl mercapto acetate) is a commercial stabilizer. The octyltin compounds are stated to be somewhat lower in tin content and to offer increased lubricity compared to their butyltin counterparts. Ejk et al. state that butyltin stabilizers possess unsurpassed stability to PVC homopolymers and copolymers while only octyltin stabilizers provide the stability, clarity and blush resistance properties required for PVC food packaging. Ejk et al. also point out that an extended production run is the only true test for a stabilizer but that laboratory tests can be used to evaluate candidates and keep the number of production runs at a minimum."

Dynamic mill stability is among the most popular methods for evaluating the dynamic activity of a stabilizer.

The water solubility of methyltin compounds is shown for example in Mack et al. patent 2,914,506 Example wherein dimethyltin, S,S' bis (2, 3-dihydroxypropyl mercaptide) is shown to be completely water soluble while the corresponding dibutyltin compound is not water soluble. Dimethyltin dichloride is also known to be water soluble.

Barnes and Stoner in British Journal of Industrial Medicine Vol. 15 pages 15-22 (1958) report on the Toxic Properties of Some Dialkyltin and Trialkyltin Salts. The article indicates that dimethyltin dichloride, while less toxic than other dialkyltin dichlorides when injected intravenously into rats, when tested on the skin produced severe superficial damage in rats and guinea pigs. Orally it was toxic in a dosage of mg/kg. Barnes and Stone also pointed out that dibutyltin di-isooctyl thioglycolate had no significant toxic difference from dibutyltin dichloride when applied orally. Trimethyltin acetate had an oral toxicity 40 times greater than that of tributyltin acetate. The trimethyl compound also was water soluble.

Barnes (co-author of the above article) arid Magos Organometal. Chem. Rev. Vol. 3 pages 137-150. Toxicology of Organometallic Compounds" on pages 143-145 discusses dialkyl and trialkyltin compounds. The article points out on page 144 that the higher homologues, dibutyl and dioctyltin salts are important stabilizers in PVC and that the lower dialkyltin compounds are intense and acute irritants and damage the skin. In contrast dibutyltin salts are stated to be not sufficiently irritating to produce skin damage. From animal studies it is stated that it would seem probable that dimethyltin salts would damage human skins.

On page 145 it is pointed out that triethyltin compounds are toxic by mouth or by injection and that trimethyltin compounds are similarly toxic while tributyltin compounds are indicated as having a lower toxicity.

Kirk Othmer Encyclopedia of Chemical Technology, 1st edition Second Supplement (1960), on page 541 points out that dimethyltin dichloride derivatives are not too compatible with polyvinyl chloride and hazy films result.

TM- is a commercial dibutyltin bis (isooctyl thioglycolate), TM-l8l is commercial dimethyltin bis (isooctyl thioglycolate) of the present invention.

Acute oral toxicity and primary skin and acute eye irritation studies were made on TM 180 and TM-l 81 using the techniques specified in the Regulations for the Enforcement of the Federal Hazardous Substances Act (Revised, Federal Register, Sept. 17, 1964). Oral toxicity (LD for TM-l 80 was 1037 mg/kg and TM- 181 had an oral LD of l 102 mg/kg. In the Patch Test for Primary Skin Irritation TM-180 had a Primary Irritation Index of 6.99 while TM 1 81 had a Primary Irritation Index of 2.36.

Eye application of TM- 1 80 to rabbits produced moderate or marked conjunctivities and thickening and fissuring of the eyelids in each rabbit tested while with TM- 181 there was no irritative efi'ects involving the cornea, iris or conjunctival.

The Summary of the report on TM-180 classified TM- 1 80 as toxic, but not highly toxic, by ingestion; is a primary skin irritant, but not a corrosive material; and is an eye irritant while TM-l8l is classified as toxic, but not highly toxic, by ingestion; is not a primary skin irritant or corrosive material; and is not an eye irritant".

The lack of skin irritation is surprising in view of the Barnes and Stoner results set forth in Table 5 in regard to dimethyltin dichloride.

In water solubility tests both TM-l80 and 3(CH proved to be quite insoluble, the solubility being about 0.025% for both compounds. Water extraction tests on polyvinyl chloride pipe containing TM-ISO and TM- l8l were conducted according to the National Sanitation Foundation (N.S.F.) tests at the indicated stabilizer levels in parts per hundred resin (phr). 5

Compound phr 72 hr. l00F. distilled H,O pans per million (ppm) stabilizer extracted TM-l80 0.6 3 t0 TM-l8l 0.54 1

c, 0 M(calc) 1300 M(exp) 1380 Further extractions were carried out with PVC pipe compound at various levels of the stabilizer. In all cases extractions in the one part per million range were obtallied.

72 hr. l00F. Distilled Water ppm Stabilizer Extracted Compound TM-l 81 is thus non extractable by water from rigid PVC (less than 1 ppm) and has been approved by the National Sanitation Foundation for use in potable water pipe. Previously the dibutyltin analogue was the sole approved tin stabilizer for such use. The suitability of the dimethyltin bis(isooctyl thioglycolate) for such purpose is particularly surprising in view of the belief that dimethyltin compounds in general are water soluble.

While TM-l 81 is slightly more volatile than TM- 180 (about 20-25C.) on thermogravimetric analysis (complete loss for TM-l8l for 3 samples average 279C. and for TM-l80 averaging 301C. while the temperature at which 50% of the material was gone for TM-l 81 was 223C. and for TM-l80 was 245C.) this is not observable in actual use. Thus in Brabender experiments with PVC at variable and high concentrations at elevated temperatures (440F), no loss in stabilization with TM-l 81 was noted and if there is any difference in loss of stabilization with TM-l8l over TM-l 80 in PVC processing, it is not apparently significant.

To reduce toxicity of formulations containing dimethyltin bis(isooctyl thioglycolate) it should be as free as possible from trimethyltin isooctyl thioglycolate. The oral toxicity of a sample of an aikyltin compound can be determined relatively accurately by the equation where It has been found that dimethyltin bis isoocetyl thioglycolate) is an exceptionally good stabilizes for vinyl chloride polymers, much better than dibutyltin bis- (isooetyl thioglycollate). in laboratory tests the superiority is not as marked as in production sized extraders where it seems on a practical basis to be up to twice as effective, pound for pound. The ability of TM-l8l to maintain good early color" in PVC is unmatched by TM-l80 at any concentration. In the first 7 months since its commercial introduction over 200,000 pounds of TM-l8l have been sold and it is rapidly gaining widespread acceptance.

in at least one case a customer reported that TM-l 81 as a stabilizer resulted in fusion of rigid PVC much more quickly than with TM-l 80. Possibly this is due to TM- 1 8l being more solvating or more plasticizing than TM-l80 at elevated temperatures such as those occurring in extruders and other processing equipment.

TM-l8l is described in its commercial literature as a liquid organotin, sulfur-containing PVC stabilizer possessing excellent compatibility and processing characteristics. It is essentially non-lubricating. TM-lSl fur nishes equivalent performance to TM-l80 with much greater economy.

Typical Physical Properties Form Clear liquid Color (Gardner) 2-3 Specific Gravity at F 1.19 Viscosity at 75F. 66 cps Lbs/Gallon 9.9

(TM-181 also has an LD of over 1000 mg/kg.) Application and Attributes of TM-l 81 1. Designed for the rigors of rigid PVC processing: single and twin screw extrusion, injection molding, blow molding, and calendaring.

2. Especially recommended as a more economical, yet equivalent performing replacement for TMl8O and other comparable products in such PVC extrusion applications as RSF and DWV pipe (Type I and ll), electrical conduit, sheet and siding.

3. Furnishes superior static and dynamic (Brabender) stability to TM-l8O and also promotes better initial color in PVC at use levels l0-20% lower than TM -l80.

4. High compatibility with PVC promotes excellent clarity--recommended for blow molding.

5. Enhances fusion of PVC powder blends; contrib utes to lower melt viscosity.

6. Recommended for solution vinyl chloride systems containing reactive terpolymers, e.g. vinyl chloride vinyl acetate-maleic anhydride terpolymers such as 86:l3:l, 8511312, 8411323.

7. Recommended for fluidized-bed powder coating applications.

While the use of dimethyltin bis (isooctylthioglycolate) is preferred in the stabilizer compositions there can also be used dimethyltin bis (isooctyl mercapto propionate Unless otherwise indicated all parts and percentages are by weight.

The stabilizers of the present invention can be used with halogen containing vinyl and vinylidene resins in which the halogen is attached directly to the carbon atoms. Preferably, the resin is a vinyl halide resin, specifically, a vinyl chloride resin. Usually, the vinyl chloride resin is made from monomers consisting of vinyl chloride alone or a mixture of monomers comprising at least 70% vinyl chloride by weight. When vinyl chloride copolmers are stabilized, preferably the copolymer of vinyl chloride with an ethylenically unsaturated compound copolymerizable therewith contains at least l% of polymerized vinyl chloride.

As the halogen resin there can be employed chlorinated polyethylene having 14 to 75%, eg 27% chlorine by weight, polyvinyl chloride, polyvinylidene chloride, polyvinyl bromide, polyvinyl fluoride, polyvinylidene fluoride, copolymers of vinyl chloride with l to 90%, preferably, 1 to 30%, of a copolymerizable ethylenically unsaturated material such as vinyl acetate, vinyl butyrate, vinyl benzoate vinylidene chloride, diethyl fumarate, diethyl maleate, other alkyl fumarates and maleates, vinyl propionate, methyl acrylate, 2- ethylhexyl acrylate, butyl acrylate and other alkyl acrylates, methyl methacrylate, ethyl methacrylate, butyl methacrylate and other alkyl methacrylates, methyl alpha chloroacrylate, styrene, trichloroethylene, vinyl ethers such as vinyl ethyl ether, vinyl chloroethyl ether and vinyl phenyl ether, vinyl ketones such as vinyl methyl ketone and vinyl phenyl ketone, l-fluorolchloroethylene, acrylonitrile, chloroacrylonitrile, allylidene diacetate and chloroallylidene diacetate. Typical copolymers include vinyl chloride-vinyl acetate (96.4 sold commercially as VYNW), vinyl chloridevinylacetate (87:13), vinyl chloridevinyl acetate- Maleic anhydride (8621311), vinyl chloride-vinylidene chloride (95:5), vinyl chloride-diethyl fumarate (95:5), vinyl chloride-trichloroethylene (95:5), vinyl chloride- Z-ethylhexyl acrylate (80:20).

The stabilizers of the present invention can be incorporated with the resin by admixing in an appropriate mill or mixer or by any of the other well-known methods which provide for uniform distribution throughout the resin compositions. Thus, mixing can be accomplished by milling on rolls at 100-l60C.

in addition to the novel stabilizers there can also be incorporated with the resin conventional additives such as plasticizers, pigments, fillers, dyes, ultraviolet light absorbing agents, densifying agents and the like.

If a plasticizer is employed, it is used in conventional amount, e.g. 30 to 150 parts per 100 parts of resin. Typical plasticizers are di-Z-ethylhexyl phthalate, dibutyl sebacate, dioctyl sebacate, tricresyl phosphate.

The tin containing stabilizers are normally used in an amount of 0.01 to l0% by weight of the resin, more preferably 0.1 to 5% of the tin compound is used by weight of the resin. There can also be included with the novel stabilizers of the present invention conventional stabilizers and antioxidents to assist in improving the properties of the halogen containing resin. Thus there can be included 0.0l-l0%, preferably 0.1-5% based on the resin of sulfur containing compounds such as dilauryl-thiodipropionate, distearyl 3,3'-thiodipropionate, dicyclohexyl-3,3'-thiodipropionate, dicetyl-3,3 '-thiodiproprionate, diethyl-3,3' thiopropropionate, dibenzyl- 3,3 thiopropionate, di-p-methoxyphenyl-Zi,3' -thiodipropionate, didecyl3,3'-thiodipropionate, dibenzyl- 3,3 thiodipropionate, diethyl-3,3'thiopropionate, lauryl ester of 3-methylmercaptopropionic acid, lauryl ester of 3-butyl-mercaptopropionic acid, lauryl ester of 3-lauryl mercapto-propionic acid, phenyl ester of 3- octyl mercaptopropionic acid.

There can also be included 0.1-10%, preferably 0.l5% by weight of the halogen containing resin of metal salt stabilizers such as Groups I and ll metal soaps, e.g. calcium stearate, calcium Z-ethylhexeate, calcium octoate, calcium oleate, calcium ricinoleate, calcium myristate, calcium palmitate, calcium laurate, barium laurate, barium stearate, magnesium stearate, zinc stearate, cadmium laurate, cadmium octoate, cadmium stearate and sodium stearate. Other metal salts can be used as lead stearate, lead silicate, aluminum stearate, etc.

There can also be added phenolic antioxidants in an amount of 0.0l10%, preferably 0.1-5%. Examples of such phenols include 2, 6-di-t-butyl-p-erosol, butylated hydroxyanisole, propyl gallate, 4,4'-thiobis(6-t-butylm-cresol). 4,4'-cyclohexylidene diphenol, 2,5-di-tamyl hydroquinone, 4,4'-butylidene bis (G-t-butyl-mcresol), hydroquinone monobenzyl ether, 2,2'-methylene-bis(4-methyl-6-t-butyl phenol), 2,6-butyl-4- decyloxy phenol, 2-t-butyl-4-dodecyloxy phenol, 2-tbutyl-4-dodecyloxy phenol, 2-t-butyl-4-octadecyloxy phenol, 4,4'-methylene-bis(2,6di-t-butyl phenol), pamino phenol, n-lauryloxy-p-amino phenol, 4,4'-thiobis(3-methyl-6-t-butyl phenol), bis [o-( l,l,3,3,-tetramethyl butyl)phenol] sulfide, 4-acetyl-,6- resorcylic acid, A stage p-t-butylphenolformaldehyde resin, 4,- dodecylo xy-2-hydroxybenzophenone 3-hydroxy -4- (phenylcarbonyl) phenyl palmitate, n-dodecyl ester of 3-hydroxy-4-(phenyl carbonyl) phenoxyacetic acid, and t-butyl phenol.

The use of epoxy compounds in an amount of 0.0l5% in the polymer compositions is also valuable. Examples os such epoxy compounds include epoxidized soya bean oil, epoxidised lard oil, epoxidised olive oil, epoxidized linseed oil, epoxidized caster oil, epoxidized peanut oil, epoxidised corn oil, epoxidized tung oil, epoxidized cotton-seed oil, epichlorhydrinbisphenol A resins(epichlorhydrindiphenylopropane resins), phenoxy-propylene oxide, butoxypropylene oxide, epoxidized neopentylene oleate, glycidyl epoxystearate, epoxidized a-olefins, epoxidized glycidyl soyate, dicyclopentadiene, dioxide, epoxidized butyl tollate, styrene oxide, dipentene dioxide, glycidol, vinyl cyclohexene dioxide, glycidyl ether of resorcinol, glycidol ether of hydroquinone, glycidyl ether of 1,5-dihydroxynaphthalene, epoxidized linseed oil fatty acids, allyl glycidyl ether, butyl glycidyl ether, cyclohexane oxide, 4-(2,3-epoxypropoxy acetophenone, mesityl oxide epoxide, 2 ethyl-3-propyl glycidamide, glycidyl ethers of glycerine, pentaerythritol and sorbitol, and 3,4-epoxycyclohexane-l, ldimethanol bis-9,10 -epoxystearate.

Likewise there can be used organic phosphites in an amount of 0.01 to 10%, preferably 014% f the halogen containing resins.

The organic phosphites contain one or more, up to a total of three, aryl, alkyl, aralkyl and alkaryl groups, in any combination. The term trialkylaryl is inclusive of alkyl, aryl, alkaryl and aralkyl phosphites containing any assortment of alkyl, aryl, alkaryl and aralkyl groups. Exemplary are triphenyl phosphite, tricresyl phosphite, tri(dimethylpheny1) phosphite, tributyl phosphite, trioetyl phosphite tridoecyl phosphite, octyl diphenyl phosphite, dioctyl phenyl phosphite, tri(octy1- phenyl) phosphite tri (nonylphenyl) phosphite, tribenzyl phosphite, butyl, dicresyl phosphite, octyl di(octylphenyl) phospite, tri (Z-ethyl-hexyl) phosphite, tritolyl phosphite, tri(2-cyclohexylphenyl) phosphite, trialpha-naphthyl phosphite, tri(phenylphenyl) phosphite, and tri(2phenylethyl) phosphite.

Of course there can also be incorporated 0.0ll0% of conventional organomethallic stabilizers such as the known organotin carboxylates and mercaptides if desired. Such materials include butyltin tris dodecyl mercaptide, dibutyltin dilaurate, dibutylin didodecyl mercaptide, dianyhydro tris dibutylstannane diol, dihydrocarbontin salts of carboxy mercaptals such as those set forth in l-leohenblcikner et al. US. Pat. No. 3,078,290. There can be included any of the vinyl chloride resin stabilizers set forth in Sayler US. Pat. No. 2,985,617.

Likewise there can be included polyol stabilizers for vinyl chloride resins in an amount of 0.01-%. Thus there can be included glycerol, sorbitol, pentacrythritol and mannitol.

Nitrogen containing stabilizers such as dicyandiamide, melamine, urea, formeguanamine, dimethyl hydantoin, guanidine, thiourea and the like also can be included in amounts of 01-10 There can even be included conventional lubricants for vinyl chloride resins such as low molecular weight polyethylene, i.e. polyethylene wax, fatty acid amides, e.g. lauramide and stearamide, bisamides, e.g. decamethylene, bis amide, and fatty acid esters, e.g. butyl stearate, glyceryl stearate, linseed oil, palm oil, decyl oleate, corn oil, cottonseed oil, hydrogenated cottonseed oil, etc.

To a mixture of 204:3 parts (1.0M) of isooctylthioglycolate, 150 parts of water, 84 parts (1.0M) of sodium bicarbonate and 300 parts of heptane there was added a solution of dimethyltindichloride, prepared by dissolving 107.5 grams (0.49M) of dimethyltin dichloride containing 0.5% trimethyltin chloride, in l 10 grams of water, over a i hour period at 2030C. After Example 2 102.2 parts of isooctlythioglycolate (0.5M) were heated with 41 parts (0.25M) of dimethyltin oxide (prepared from dimethyltin dichloride containing 0.5% trimethyltin chloride) for 1 hour at 100C. under vacuum. The yield was 138.5 parts (100%) of dimethyltin bis(isooctyl thioglycolate) with properties similar to those in Example 1.

DlMETl-lYLTlN BlS(lSOOCLYL-3 -MERCAPTOPROPION ATE Example 3 in a 1 liter flask there were placed 218.5 gms. (1.0M) of isooctyl-3-mercaptopropionate, 200 grams of water, 84 grams (1.0M) of sodium bicarbonate and 300 gms. of heptane. To this slurry was added a solution of 109.7 grams (0.50M) of dimethyltin dichloride (containing 0.5% of trimethyltin chloride) in 110 grams over a 1 hour period. After a short stirring period the organic layer was separated, washed and stripped under vacuum, resulting in a 287 gram yield (99%) of dimethyltin bis( isooctyl-3-mercaptopropionate), a colorless oil. This compound had a refractive index at 25 of 1.5062, a tin content of 20.3% and a sulfur content of 10.8%.

DIMETHYLTIN BlS( ISOOCTYLTHIOGLYCOLATE) Example 1 In a 1% liter flask 65.9 grams of dimethyltin oxide (0.40M) was heated with 174.7 grams (0.80M) of isooctyl-3-mercapto-propionate for 1 hour at 100C. under an absolute pressure of 2mm of Hg. The colorless oil prepared in this manner was cooled and filtered to yield 232 grams of dimethyltin bis(isooctyl-3- mercaptopropionate).

l l l 2 DISPROPORTIONATION Exa Twin Screw mph 375F. Oven a (cH hsmcl +sncl (CH s C] 5 gabiliszgr Parts lst Color (Minutes) Failure (Min.)

-l 0.40 40 TM- 1 81 0.36 50 1?. sample of dimethyltin dichloride having a trimethyltln content of 5.0% was used to prepare dimethyitin bis(lsooctylthioglycolate) by the method given in Ex- 10 ample I. This product had an LD value of 300. When Sing}; Screw 400 Oven this same dimethyltin dichloride (containing the 5.0% S'abil-lm Pans [st Color (Minutes) Failure with) tnmethyltin chloride) was heated at 120C. for 2 hours TM-1s0 1.40 10 with 2.6% by weight of stannic chloride, the trimethyltin chloride content was reduced to 0.5% and dimethyl- 5 tin bis(isoctylthioglycolate) repared from this material has an L1) rating of 1080' Conclusion: TM-l8l furnishes better color stability than TM-l80 to both a single screw and a twin screw Example 6 type of polyvinyl chloride pipe compound.

TM-lSl was compared with TM-180 as a stabilizer 20 88 Stab'my Brabcnder Plastograph for Geon I03 E? (a polyvinyl chloride medium molec- Condmons 0 rpm, charge 60 grants m weight h0mopo|ymer) The formulation employed was the Twin Screw for- L Oven Stabimy a mulation used in Example 6 part 2 with the parts of stabilizer indicated below.

Stabilizer Parts Fusion Max Torque Stability Minimum (time min.) (time min) Torque Low TM-I80 0.40 2.2 2700 3.1 1900 Level TM-I81 0.36 1.8 3425 5.6 1725 lnter- TM-l80 0.60 3.8 2400 6.1 1600 mediate Level TM-1s1 0.53 1.7 3950 6.9 1725 High TM-l80 0.80 1.5 3200 8.7 1600 Level TM-lBl 0.72 1.2 3850 9.0 1600 Conclusion: TM-l8l is clearly superior to TM-l80 in Test Formulation processing stability and color stability during process- F P ing even at a 10% lower use level. As the total stabilizer Distearyl oxolate containing 5% f mark acid Q5 Pam level is reduced is reduced the advantage shown by Stabilizer As indicated FM-181 is more pronounced.

4. Twin Screw Extrusion A series of pipe extrusions were can'ied out in Linz. Austria on an AGM CT 90/6 conical twin screw ex- Time in Mint"? truder using TM-l 80 and TM- 1 8| in the preparation of TM 0 15 7 pm color 45 2-inch SDR 2i, Type I, Grade I pipe.

TM-I80 1.0 l 4 4 4 4 6 9 10 2 g g g i a Formulation 1 Formulation 11 TM-1s1 0.8 I 2 2 3 5 9 10 TM-18l 0.75 1 2 2 3 7 l0 2%;{3 Ep pans $3 23 EP pans Color Scale I to lo 50 o L0 I L0 Ca stearate 0.4 Ca stearate 0.4 Advawax I65 1.4 Advawax 165 L4 TM-l80 0.6 TM-l8l 0.54 Conclusion: TM-l8l offers superior early color over Mixing; 1 n "I'M-180 even at significantly lower levels. Time 6 mi: 15 sec 6 1:2 23 sec Tern erature I20 2. Oven Stab1l1ty, twin and single screw extrusion for s 5 BulkPDenmy 5% 8mm 600 gm!" mulations Pipe Quality Acetone OK OK Methylene chloride OK OK Twin Screw Single Screw Dr l a i OK OK Geon I03 I00 parts Geon 103 I00 parts Oven (porosity) none none K I20 N -5 K 120 N 10 Quick Burst 52 ATM 53 ATM TiO 1.0 TiO, L0 0 (630 psi or Ca stearate 0.4 Ca stearate L0 42 ATM min) Advawax I65 1.4 Advawax 280 0.75 Output Rate I50 lbs/hr 170 lbs/hr Stabilizer as indicated Stabilizer as indicated K 120 N is a commercial acrylic processing aid, it is Conclusion: TM-181 exhibited a higer output rate and a methyl methacrylate polymer (90% methyl excellent overall performance at a 10% lower use level.

metharcrylate-- 10% ethyl acrylate).

Advawax is paraffin wax. Adv-awax 280 is ethylene bis(stearamide).

5. Single Screw Extrusion TM-i 8 l was evaluated in a commercial impactmodifled polyvinyl chloride conduit compound at a 20% l3 14 lower use level than TM- 180. Using a Prodex 3 l /2 inch -contlnued 24:1 extruder the compounds were extruded from powt g1 as indicated der, then sub ected to two addltlonal extrusions from Mm Dynamic 3900K Bmbenderv 190C regrlnd. TM-l 81 performed successfully in thls evalua- 50 rpm, 60 grams tion. 5

' phr lst color Failure lst color Failure Corroswe proPeru'es I 1.6 20 minutes 26 minutes l2 minutes l8 minutes Several commercial tln stabilizers are highly acidic in 1.4 l8 minutes 24 minutes l0 minutes l4 minutes nature, and in fact contained L8 to 2.0 chlorine which is readily hydrolyzed, forming HCl.

Steel bars were immersed in TM-l8l and one such 10 At equal levels TM-181 furnished about 8% greater competitive commercial stabilizer and allowed to stand stability (both early color and ultimate processing staat room temperature for several days. Severe corrosion bility) then a competitive commercial tin stabilizer. At occurred on the steel bar in the presence of the coma 12% lower use level TM-l8l furnished equivalent petitive stabilizer while the TM-l8l exhibited no corrotwo roll mill dynamic stability and slightly less Brasive tendencies on the steel bar immersed in it. This re- 15 bender stability. sult is significant since corrosion is a property that po- Failure is indicated in the above tests by sticking or tentially can be costly in terms of mixing extruding, mebad color or both. tering and additive handling equipment. 2. Injection Molding of Pipe Fittings E l A comparison was made of TM-18l (1.7 phr) and Xamp e 20 TM-lSO (2.0 phr) stabilized polyvinyl chloride pipe fit- This example further shows the performance profile ting compounds in an HPM reciprocating screw injecfor TM- 1 81. tion molding machine. Pipe fittings containing the TM- l8l were whiter than the TM-ISO stabilized fittings, 1. Dynamic Processing Stability Formulation which exhibited slight burning near the gates. 1000 Parts 3. Pipe Extrusion Trail K 120 N 2.0 Chlorinated polyelhylem The performance of TM-l8l m a variety of slngle X P and twin screw extractors and comparison with TM- gtgwfi '55" 1:3 l is illustrated by the following representative extru- Calcium stearate L0 SlOfl tUflS.

Extrusion Pipe Size Stabilizer phr Output Pipe Quality Type (inches) lbs/hr Appearance APM A/4/80 2 TM-I80 0.6 206 Good quality APM A/4/80 2 TM-l8] 0,5 209 Excellent color APM A/4/80 2 TM-l8l 04 213.5 Excellent pipe AGM CT Ill/8 8 TM-l8l 0.5 530 Excellent, high gloss AGM Cl lllls (thin wall) l5 TM-lSl 0.5 540 Excellent AGM Cl M118 3 TMlBO 06 500+ Good quality AGM CT lll/B 3 TM-l8l 054 500+ Whiter than standard AGM CT lll/s 3 TM-l8l 0.4a 500+ Slightly whiter than standard standard is TM |80 B. Single Screw Extrusion Extruder Type Pipe Size Stabilizer Usage Output Pipe Quality (inches) Level lbs/hr Appearance m; 3%" 24:l 8 TM-l80 standard 320 3%" 24:l 8 TM-l8l 10% below standard 328 Excellent Whiter than standard 4%" 24:l l2 TM-l8O standard 700 4%" 24:l l2 TM-l8l l5% below standard 700 Excellent whiter than standard 2%" 24:l 2 TM-l80 standard 170 2%" 24:! 2 TM-lBl l5% below Whiter than standard I 70 standard Davis Standard 3%" 24:! 4 TM-lBO L0 phr 386 production standard 3%" 241l 4 TM-l8l 0.9 phr 383 Equivalent to standard 3V2" 24:i 4 TM-lBl (1 phr 392 Equivalent to standard 3%" 24Il 4 TM-lBl 0,80 phr 4(16 1 5 Conclusion: At lower use levels (l-30% lower) TM- 181 can provide both higher quality and increased output rates on twin and single screw pipe extrusion lines than TM-l 80.

Customers have reported (a) that TM-l81 is more effective than TM-l80 in stabilizing chlorinated PVC at high temperature; (b) that Type 1 PVC pipe having a 2500 psi design stress rating has been obtained with TM-l8l (normal design stress for Type I PVC pipe is 2000 psi), and (c) TM-l8l can be used in high distortion teleduct (conduit) PVC.

As used in the present specification and claims the isooctyl group is the mixture of isomers produced in the oxo process. This is the normal meaning of isooctyl when used with conventional tin stabilizers such as dibutyltin bis (isooctyl thioglycolate) as is set forth in Kirk-Othmer Encyclopedia of Chemical Technology 1st edition, Second Supplement (1960) page 540. A typical commercial mixture of isomeric octyl alcohols used to prepare the isooctyl thioglycolate is shown in Kirk-Othmer on page 552 and the usage of the term iso" is explained on pages 553-554.

As used in the claims the term LD of at least 1000" means that the LD is at least 1000 or greater, eg 1000, H00 or 1380.

The dimethyltin bis(isooctyl mercaptoalkanoates) of the invention are compatible with polyvinyl chloride as is evident from the data presented supra and do not cause hazy films.

In place of the dimethyltin bis(isooctylmercaptoalkanoate) there can be employed the corresponding dimethyltin bis( Z-ethylhexyl thioglycolate) and dimethyltin bis(2-ethylhexyl-3-mercaptopropionate) as stabilizers for the halogen-containing resins, e.g., polyvinyl chloride. The dimethyltin bis( 2-ethylhexyl mercaptoalkanoate) can be prepared in an identical manner to that shown in Example 1, replacing the isooctylthioglycolate by a mole of 2-ethylhexyl thioglycolate (or 1 mole of 2-ethylhexyl-3-mercaptopropionate).

[t has now been found that not only the dimethyl compounds prepared and used in Examples 1-7 can be prepared with low toxicity but that also all of the other compounds within formula I can likewise be prepared with low toxicity by reducing the amount of trimethyltin product in the same manner by preparing the materials either using dimethyltin dichloride of low toxicity due to the reduction in trimethyltin chloride, e.g., as prepared in Example 1, or using dimethyltin oxide of low toxicity due to the reduction in trimethyltin compounds because of preparation of the dimethyltin oxide by the method indicated broadly in Example 2.

The only change in the procedures normally used for the preparation of the compounds of formula I (which compounds are old per se) is to employ as a basic starting material dimethyltin chloride having a very low amount of trimethyltin chloride. It was not previously recognized that the presence of trimethyltin compounds was the reason for toxicity of dimethyltin compounds.

As shown in Example 5 the amount of trimethyltin chloride present in dimethyltin dichloride is reduced by adding SnCl to dimethyltin dichloride. The use of excess SnCl e.g., or in the process of Example 5 merely increases the amount of monomethyltin chloride in the dimethyltin dichloride but it further assures the reduction in amount of trimethyltin chloride.

The products of the present invention preferably should have an LD of at least 1000 when administered orally to rats. This can be accomplished by assuring that the trimethyltin content in the dimethyltin compounds of formula I is so low that not more than 0.75% of the tin as metal is in the fonn of trimethyltin compounds. Any way which assures that the amount of tin present as trimethyltin compound is not over 0.75% of the total tin as metal in the dimethyltin compounds can be used to prepare such compounds. As indicated above, the starting materials are preferably made from dimethyltin dichloride treated to reduce the trimethyltin chloride so that not over 0.75% of the tin as metal is present as trimethyltin chloride. Using this starting material (or dimethyltin oxide prepared therefrom) conventional procedures are employed, such as those illustrated in Examples l-A.

Less preferably there can be used dimethyltin bis- (isooctyl thioglycolate) and any of the other dimethyltin compounds having sufficient trimethyltin compound to have an LD of up to 695 mg/kg of body weight.

Dimethyltin sulfide can be prepared, for example, by reacting 1 mole of dimethyltin dichloride with one mole of sodium sulfide and compounds such as sodium methyl mercaptide or sodium isooctyl mercaptide, for example, can react with the purified dimethyltin dichloride by the conventional procedure to form dimethyltin dimethyl mercaptide or dimethyltin diisooctyl mercaptide. The general reaction procedures are further illustrated in Kirk-Othmer Encyclopedia of Chemical Technology, Second Supplement Volume (i960), pages 532-533.

In the case of dimethyltin bis(isooctyl thioglycolate) or dimethyltin bis( Z-ethylhexyl thioglycolate) the amount of trimethyltin isoocytl thioglycolate present amounts to 0.5 weight this amount corresponding to about 0.7 5% of the total tin present calculated as metal being present as trimethyltin compound.

The amount of trimethyltin compounds present can be reduced to zero but is normally reduced to not over 0.15% of the total tin present calculated as metal since the greater the reduction in amount of trimethyltin compound the greater the increase in cost.

It has further been found that particularly valuable stabilizer compositions for any of the above identified halogen containing resins can be prepared if there is used a mixture of a compound having the formula l )1 and a compound having the formula (2):

CH3 Sn lslcmncooan, and containing not over 0.6%. preferably not over 04% especially for food or potable water uses, of the compound having the formula (3) icumsn S(CH,),,COOR;. where n and R are as defined above. Based on the total of l (2) and (3) the amount of (2) is 4 to 40%, more usually 19-29 weight percent and l is 96 to 60%,

more usually 8l-7l weight percent.

Typical compounds of formula (2) are:

methyltin tris(isooctyl thioglycolate),

methyltin tris(isooctyl-3-mercaptopropionate),

methyltin tris( 2-ethylhexyl-thioglycolate methyltin tris( 2 -ethylhexyl 3 -merc apto-propionate),

methyltin tris( isooctyl-4-mercaptobuty rate methyltin tris(n-ctyl thioglycolate),

methyltin tris(n-octyl-3-mercaptopr0pionate),

methyltin tris(methyl thioglycolate),

methyltin tris(methyl-3-mercaptopropionate),

methyltin tris( meth'yl-4-mercaptobutyrate),

methyltin tris(ethyl thioglycolate),

methyltin tris( propyl-3-thiopropionate),

methyltin tris( butylthioglycolate methyltin tris( butyl-3-thiopropionate methyltin tris( butyl-4-thiobutyrate methyltin tris( isooctyl-Z-thiopropionate methyltin tris(decyl thioglycolate),

methyltin tris(isodecyl thioglycolate),

methyltin tris(dodecyl thioglycolate),

methyltin tris(dodecyl-3-thiopropionate),

methyltin tris(isodecyl-3-thiopropionate),

mehtyltin tris( dodecyl-4-thiobutyrate methyltin tris(octadectyl thioglycolate),

methyltin tris(octadecyl-3-thiopropionate),

methyltin tris(octadecty-4-thiobutyrate),

methyltin tris(eicosanyl thioglycolate),

methyltin tris(eicosanyl-3-thiopropionate),

methyltin tris( cyclopentyl thioglycolate methyltin tris(cyclohexyl thioglycolate),

methyltin tris(cyclohexyl-3-thi0propionate),

methyltin tris( benzyl thioglycolate),

methyltin tris( benzyl-3-thiopropionate),

methyltin tris(phenyl thioglycolate),

methyltin tris(p-tolyl-3-thiopropionate),

methyltin tris(allyl thioglycolate),

methlytin tris(allyl-3-thiopropionate),

methyltin tris(allyl-4-thiobutyrate),

methyltin tris(crotyl thioglycolate),

methyltin tris(oleyl thioglycolate),

methyltin tris(oleyl-3-thiopropionate),

methyltin tris(oleyl-4-thiobutyrate),

methyltin octyl thioglycolate bis(decyl) thioglycolate,

methyltin tris(methallyl thioglycolate),

methyltin tris( methallyl-3-thiopropionate),

methyltin tris(dodecenyl thioglycolate).

As the compounds of formula (1) there can be used any of those mentioned previously as well as dimethyltin bis(isodecyl thioglycolate) and dimethyltin bisisodecyl thio-3-propionate The trimethyltin compounds of formula (3) are the impurities still retained after forming the dimethyltin compounds, e.g., in the manner specified above.

The Formula T mentioned below contained about 24 weight monomethyltin tris(isooctyl thioglycolate), 0.6% trimethyltin isooctyl thioglycolate, and the balance dimethyltin bis(isooctyl thioglycolate).

For food contact stabilizer work a similar formulation has been found satisfactory but containing approximately 24 weight monomethyltin tris(isooctyl'thioglycolatc). The food contact stabilizer formulation has been tentatively approved in Germany, The Netherlands and England.

Polyvinyl chloride bottles containing 2.2% of Formula T were tested for migration of the stabilizer into (a) distilled water, (b) 3% acetic acid, (c) l0% ethanol, (d) 50% ethanol, and (e) peanut oil at 23 C. and 50C. in tests lasting 3, l0 and 24 days. In all cases. migration of the stabilizer was found to be well below I ppm. The maximum migration even at 50C. barely exceeded 0.2 ppm, corresponding to about 0.03 mg/dm indicating the Formula T is well suitable for use as a stabilizer for polyvinyl chloride for the manufacture of food packaging material.

Polyvinyl chloride pipe having an inner diameter of 10 cm and a wall thickness of 3 mm. containing approximately 0.7% ADVASTAB as a stabilizer was tested for suitability as a potable water pipe.

Sections of the pipe were filled with NaHCO solution and with NaHCO: solution containing chlorine and stored for 2, 5 and 10 days. Both solutions were analyzed for migration of tin stabilizer. The migration in all cases was less than 0.01 mg/dm The potassium permanganate consumption of the NaHCO solution in all cases was less than 3 mg] l. The NaHCO;,-chlorine solutions had a mean value in the 10 days test of less than 2mg/m per day. Therefore, there is no health risk in using the pipe for potable water.

Subdionic toxicity studies were done on Formula T by day rat feedings at levels of 0, 10, 30, and 300 ppm. There was no toxic effect at I00 ppm or lower and slight toxic effects were noted at 300 ppm.

As a result of other tests on Formula T, the British industrial Research Association indicated that it could be included in the BlBRA/BPF Code of Recommendations, at a maximum of 2.5% in polyvinyl chloride intended for food-contact use.

The following examples show that stabilizer formulations within the present invention impart excellent stability to polyvinyl chloride. The color ratings are on the usual 0 to 10 scale with 0 being colorless and 10 being black except in Example 11 wherein the scale ranged from 0 being milky white to ID being milky brown.

Example 8 Polyvinylchloride (Geon I03 Ep-8) 100.0 weight Stearyl alcohol 0.5 weight Stabilizer (Table 2) 2.0 weight The above formulations were mixed together on a two differential roll laboratory mill at C. for 5 minutes until thoroughly homogenized. The resulting sheet was then taken from the roll at a thickness of 0.6 mm. and samples were heated in a gear-oven at C. These samples were examined visually for rate of color development. In a further test, the two roll sheet was pressed in a press at 150 kg/cm for 50 minutes at C. at a thickness of 1 mm. The resulting sheets were examined visually for rate of color development.

TABLE 1 STABILIZER a. Dimethyltin bis(isooctyl thioglycolate) b. Monomethyltin tris(isooctyl thioglycolate) c. Trimethyltin isooctyl thioglycolate d. Dimethyltin dilaurate e. Monomethyltin trilaurate f. Dimethyltin bis(isooctyl maleate) g. Monomethyltin tris(isooctyl maleate) TABLE 2 Results Corn- Sta Color of Test Piece Color of pound bill Weight (minutes)* Pressed No. zer Phr Parts 20 40 60 90 120 Sheet 1 a 1.8 89.5 0 0 3 a Colorless b 0.2 10.0 c 0.01 0.5 2 a l.6 79.5 0 0 0 3 8 Colorless b 0.4 20.0 c 0.01 0.5 3 d 0.8 90.0 5 Orange e 0.2 10.0 4 d L6 110.0 a 7 10 Yellow Brown e 0.4 20.0 5 f l .8 90 l 3 7 l0 Colorless 6 l' l .6 800 l 3 9 l0 Colorless g 0.4 20.0 7 a 2 .0 l 00 .0 l l 2 7 9 Colorless a b 2.0 100.0 a 10 Yellow 9 d 2 .0 I 00.0 5 5 l0 Orange l0 e 2.0 l00.0 6 10 Brown 1 l f 2.0 l00.0 l 2 3 l0 Colorless 12 g 2.0 100.0 10 Yellow Colorless 101 Yam/131 Brown (7) ammo) The results clearly show that the vanat1on 1n the m 4 cominued acidic components gave significant differences 1n heat stability. C

om- Sta- Color of Test Piece (Minutes)' The thioalkanoates had a remarkably improved efpound 011- Weight feet over the aliphatic carboxylate and the alkyl male- PM 20 60 90 ate. c 0.01 0.5

. a a 1.2 00.0 0 0 1 7 9 Example 9 b 0.8 40.0 t c 0.01 0.5 PVC (polyvinyl chloride) sheets were prepared In a 9 l 8% 23-8 0 0 l 5 9 manner similar to that described in Example 8 and R were checked for rate of color development. l0 0 0 1 4 9 10 b 1.0 50.0 TABLE 3 STABILIZER 11 a 1.94 91.0 1 1 2 s 9 a. Dtmethyltin bis(isooctyl thioglycolate) bM 11111'1" r1111 1 1 onome y n ns(1soo cy 10g you ate) 1 11 1.1; 90.0 0 1 2 4 9 c. Tnmethyltm isooctyl thioglycolate 40 1 h. Dibutyltin bis(isooctyl thioglycolate) I ,3 23 3 0 2 9 i. Monobutyltin tris(isooctyl thioglcyolate) 14 j L8 900 1 2 4 6 9 j. Dioctyltin bis(isooctyl thioglycolate) f 3 g .133 3 6 9 k. Monooctyltin tris(isooctyl thioglycolate) k 0.4 20.0 l. Dimeth ltin bis 2-eth lhex l-beta-merca to roa 2D l 2 7 9 y y y p P 1'! b 2.0 100 8 10 pionate) Colorless (0) Yellow (3) Brown (7) Black ([0) m. Monomethyltin tris(Z-ethylhexyl-beta-mercaptopropionate n. Trimethyltin Z-ethyIheXyI-beta-mercaptopropionate Table 4 Results Com- Sta- Color of Test Piece (Minute-51" pound bil- Weight No. izer Phr Parts 20 40 60 90 l 20 l 8 L9 94.5 0 0 l 5 B b 0.] 5.0 c 0.0l 0.5 2 l 1.9 94.5 0 0 0 2 8 m 0.l 5.0 n 0.0l 0.5 3 3 L8 89.5 0 0 0 3 8 b 0.2 10.0 c 0.0! 0.5 4 a [.7 84.5 0 O 0 3 8 b 0.3 l5.0 c 0.0l 0.5 5 a l.6 79.5 0 0 0 3 8 b 0.4 20.0 c 0.0l 0.5 0 0 0 3 3 6 l 1.6 79.5 0 0 0 2 R m 0.4 20.0 n 0.01 0.5 7 a 1.4 69.5 0 0 0 4 8 and heat stability.

Example l0:

Polyvinylchloride (Geon I03 Ep-S) Calcium Carbonate (OMYA-QOT) Low M.W. Polyethylene (AC-629A) Calcium Stearate Paraffin Wax (ADVAWAX I65) Titanium Oxide Stabilizer Pr-rPPlu-IONONO Weight part Weight part Weight part Weight part Weight part Weight part Weight part The above formulations were mixed together on two differential roll laboratory mill at 200 C. for 5 minutes until thoroughly homogenized. The resulting sheet was then taken from the roll at a thickness of 0.6 mm. and samples were heated in gear-oven at l C.

These samples were examined visually for rate of color development.

TABLE STABILIZER a. Dimethyltin bis(isooctyl thioglycolate) b. Monomethyltin tris(isooctyl thioglycolate) c. Trimethyltin isooctyl thioglycolate j. Dioctyltin bis(isooctylthioglycolate) Table 6 Results Com- Sta- Color of test piece (Minutesf pound bil- Weight Initial No. izer Phr Parts Sheet l a 1.47 73.4 I 4 6 8 8 9 b 0.52 26.0 c 0.01 0.6 2 a 1.89 94.3 2 7 8 9 10 10 b 0.09 4.5 c 0.02 1.2 3 2.0 4 7 8 9 l0 l0 Colorless (0) Yellow (3) Brown (7) Black (10) The results indicate that increase in the quantity of incorporated tn'methyltin compound decreased the heat stability effect. The methyltin stabilizer was better than the octyltin stabilizer.

Example l l:

Polyvinyl chloride (Geon 103 Ep-S) 100.0 Weight Parts Calcium Carbonate (OMYA-QOT) 3.0 Weight Parts Low Molecular Polyethylene (AC-629A) 0.2 Weight Parts Carcium Stearate 0.6 Weight Parts Paraffin Wax (ADVAWAX 165) 1.2 Weight Parts Titanium Oxide 1.0 Weight Parts Stabilizer 0.3 Weight Parts The above formulations were rolled out on a two roll differential roll laboratory mill at l C. The resulting sheets were taken from the roll at a thickness of 0.3 mm at 10 minute intervals and were checked for rate of discoloration.

TABLE 7 STABILIZER a. Dimethyltin bis(isooctyl thioglycolate) b. Monomethyltin tris(isooctyl thioglycolate) c. Trimethyltin isooctyl thioglycolate h. Dibutyltin bis(isooctyl thioglycolate) i. Monobutyl tin tris(isooctyl thioglycolate) 3O Stabilizer (Table 10) 22 j. Dioctyltin bis(isooctyl thioglycolate) k. Monooctyl tin tris(isooctyl thioglycolatc) The results at dynamic heat stability clearly show that the combination of monomethyl tin compound into dimethyl tin compound gave significantly improved stabilizing effect compared to the use of monobutyl tin compound with dibutyl tin compound and the use of monooctyl tin compound with the dioctyl tin compound.

Example 12:

Polyvinylchloride (Geon 103 Ep 8) MBS Resin (Kanc Ace 13-12) (monobutyl styrene resin) Stearyl Alcohol 1000 Weight Parts l0.0 Weight Parts 0.5 Weight Parts 20 Weight Parts The halogen-containing vinyl resin formulations were sheeted out in a manner similar to that described in Example 8 and were compared for rate of color develop- 35 merit.

TABLE 9 Stabilizer a. Dimethyltin bis(isooctyl thioglycolate) b. Monomethyltin tris(isooctyl thioglycolate) c. Trimethyltin isooctyl thioglycolate h. Dibutyltin bis(isooctyl thioglycolate) j. Dioctyltin bis(isooctyl thioglycolate) (In place of MBS there can be incorporated ABS (acrylonitrile-butadiene-styrene terpolymer) and other 5 impact modifiers. there also can be added conventional processing aids.)

Table 10 Results Com- Sta- Color of Test Piece (Minutes? Color pound bil- Weight initial of No. izer Parts Sheet 20 40 6O 90 Press Sheet 1 a 89 5 0 0 0 l 2 4 Colorless b 10.0 c 0.5 2 a 79.5 0 0 0 0 l 5 Colorless b 20.0 c 0.5 3 a 59.5 0 0 0 2 3 9 Colorless b 0.8 40.0 c 0.01 0.5 4 a 1.0 49.5 0 0 l 3 5 l0 Pale Yellow b L0 500 c 0.01 0.5 5 h 2.0 100.0 3 5 5 7 8 9 Yellow 6 j 20 100.0 4 5 6 8 8 9 Yellow 7 u 2.0 100.0 I 2 2 2 3 7 Colorless 8 b 2.0 100.0 0 1 9 7 Pale Table l-continued Results Com- Sta- Color of Test Piece (Minutes)* Color pound bil- Weight Initial of No. izer Phr Parts Sheet 20 40 60 90 120 Press Sheet Yellow 9 c 2.0 100.0 3 5 5 7 B 9 Dark Yellow Colorless (0) Yellow (3) Brown (7) Black( 10) The results indicate the significantly improved effect of the combined stabilizer of the invention in the poly mer blend of MRS and halogen-containing vinyl resin compared to the dibutyltin and dioctyltin compounds.

lt has been further found that the amount of monomethyltin ester in the mixture of compounds of formulae (1), (2) and (3) above, can be extended so that the mixture contains 4 to 98% of the monomethyltin ester, correspondingly 96 to 2% of the dimethyltin ester and not over 0.6% of the trimethyltin ester. Preferably the amount of trimethyltin ester is even lower, e.g., not over 0.4%, and even as low as 0.01% or even lower.

It has been found that dimethyltin derivatives of alkylthioglycolates undergo a redistribution reaction on thermolysis with consequent formation of various trimethyltin compounds. This phenomenon, with respect to isooctylthioglycolates, is governed by the equilibnum:

2(CH ),Sn(lOTG CH;,Sn(lOTG (cH,),sni0ro D M T The equilibrium constant was determined to be:

Therefore, the increasing presence of the monomethyltin derivative will reduce the theoretical equilibrium concentration of the trimethyltin compound in a manner described by the equation (1) above.

In the drawings:

FIG. 1 is a graph of the thermolysis at 180C. of three different dimethyltin bis( isooctylthioglycolate) compositions;

FlG. 2 is a thermolysis graph similar to that of FIG. 1;

FIG. 3 is a graph of the equilibrium mixtures of methyl and dimethyltin isooctylthioglycolates at 180C. and calculated final concentration of trimethyltin isooctylthioglycolate using the equilibrium constant equation (1), supra; and

FIG. 4 is a graph similar to FIG. 3 but limited to starting concentrations of monomethyltin tri(isooctylthioglycolate) of 80% or above.

The concentrations of D, M and T as determined by equation 1 for the equilibrium constant are set forth below in Table and as mentioned, supra, are illustrated graphically in FIGS. 3 and 4.

The rate at which trimethyltin isooctylthioglycolate is formed depends on the concentration of the monomethyltin compound [see equation (2), infra] the higher concentrations of the latter material will slow the formation of the trimethyltin derivative.

Rate. dr/dr k, {m m [T] (2) Experiments, in which the composition of mixtures ver sus time at 180C. were determined, and carried out with 100 percent dimethyltin bis-isooctylthiogylcolate and with mixtures containing monomethyltin tris-isooctylthioglycoalte. The mixtures contained 19 percent, 28.6 percent, and 80.0 percent by weight monomethyltin derivative. The experimental results are collated in Tables 1 1, 12, 13 and 14 and are plotted in FIGS. 1 and 2.

Thus, by increasing the amount of monomethyltin ester in the original mixture with dimethyltin ester the formation of trimethyltin ester at elevated temperatures is effectively repressed. This is important in utilizing the methyltin esters in stabilizing halogen containing resins since such resins are normally hot processed, e.g., at ISO-200C. as a result of which even if the initial amount of trimethyltin ester in the stabilizer is initially low it will gradually build up unless there is used a substantial amount of the monoester in admixture with the starting diester. Desirably the monoester, e. g., monomethyl tin tris(isooctylthioglycolate) is or more preferably or more of the total of monomethyl and dimethyltin esters to insure keeping the formation of trimethyltin ester to a minimum during the hot processing.

Thus in Example 8, in place of Compound 1 there can be used either 20% (0.4 phr) of (a) and 80% (1.6 phr) of (b) or 2% (0.04 phr) of (a) and 98% (1.96 phr) of (b) to insure repression of the formation of (c) during the processing at C., C. and C.

In place of the isooctyl ester there can be used any of the other mono and dimethyltin esters in formulating stabilizer compositions having large amounts of methyltin monoester, e.g., above 40% of monoester and preferably 75% or even more of monoester based on the total of monomethyltin ester and dimethyltin ester to insure suppression of fonnation of trimethyltin ester at elevated temperature. The starting amount of trimethyltin ester as indicated is desirably kept as low as possible, e.g., 0.6% or less, more preferably 0.4% or less and with even greater advantage is 0%.

TABLE 1 1 Thermolysis of Dimcthyltin bis lsooctylthioglycolate Cone. of Methyltin TABLE 12 Thermolysis of Mixture of Methyltin Isooctylthioglycolates Cone. of Methyltin What is claimed is:

l. A pipe comprising a halogen containing resin selected from the group consisting of chlorinated polyethylene a vinyl halide resin and a vinylidene halide Sam le Time lsooct lthio l colates, Wt 5 g (min) wL MONO. y w gg wt resin w1th a stabihzmgly effective amount of a mixture of l) 60 to 96% of a compound having the formula 111 28.6 71.4

la 27.0 69.2 1.0 2 25.9 66.5 1.3 (3H:' (CHUHCOOR: 3 25.8 62.8 1.8 4 28.5 56.2 1.9 0 ,Hlld 5 60 31.0 60.1 4.3 6 90 29.8 53.0 7.3 CHa c11., ,.co0R

2. 4 to of a compound having the formula TABLE 13 5 ca 86 (SrCmncmnm v not over 0.6% of Thermolysis of Methyltin lsooctylthioglycolates Mixture and ha at 180C (Tone. of Methyltin CH- Sample Time lsooctylthioglycolates. Wt Number (min) Wt. MONO Wt. Dl- Wt. TRI- CH, nS(CH,),,COOR=,

la 5 1.0 2 10 20.1 74.3 1.6 3 20 22.7 73.4 1.9 as an impurity in the stabilizer and where R is hydro- 35 carbon of up to 20 carbon atoms and n is an integer of 5 27.1 59.7 5.8 6 90 27.4 59.3 5.3 l to 3. l

25 2. A pipe according to claim 1 wherein the stabilizer has an LD of at least 695 when administered orally to TABLE 14 3. A pipe according to claim 2 whereln R 15 alkyl, cy- Themmlysis ggfg Mim'es cloalkyl, alkenyl or benzyl and the LB of the stabilizer COHC. 6r Methyltin 30 15 at least 1000. Sample Time Isooctylthioglycolates, Wt alk of Number (min) wt MONG wL DL wt Tm; 4. A pipe according to clalm 3 vvherem R 15 y 4 to 12 carbon atoms and n 18 an integer of l to 2. W4 0 130.0 19.7 0.3 n 1 f [a 5 790 200 (l S. A pipe according to claim 4 wherein R is y 2 10 81.0 18.4 1 8 to 12 carbon atoms. 2 I: 5 35 6. A pipe according to claim 3 wherein the stabilizer 5 60 75.9 19.1 2 is present in an amount of 0.1 to 5% by weight of the 6 72.3 17.7 -2 resin TABLE I5 Equilibration oi Mixtures of Monoand Dimethyltin lsooctylthioglycolates at C Mole 7o: Monoi- Tri- Wt. 70 Mono- Di Tri Initial 99.0 1.0 0 99.25 0.747 Equilibrium 99.0 0.997 0.001 41 99.25 0.745 0.000692 Conc. Initial 98.66 1.34 0.0 99.0 1.00 0.0 Equil. 98.66 1.335' 0.00253 99.0 0.999 0.00125 1611161 97.0 3.00 0.0 97.75 2.25 0.0 Equil. 97.01 2.987 0.0128 97.76 2.23 0.00637 Initial 95.00 5.00 0.0 96.22 3.78 0.0 Equil. 95.04 4.964 0.0358 96.26 3.72 0.0179 lnltlill 93.46 6.54 0.0 95.0 5.0 0.0 Equil. 93.52 6.42 0.0617 95.07 4.90 0.0313 Initial 92.0 8.0 0.0 93.91 6.09 0.0 Equil. 92.09 7.81 0.0931 94.01 5.95 00469 161061 90.0 10.0 0.0 92.35 7.65 Equil. 90.15 9.71 0.147 92.50 7.42 0.0744 Initial 87.02 12.97 0.0 90.0 10.0 0.0 Equil. 87.27 12.47 0.25 90.26 9.61 0.128 Initial 85.00 15.00 0.00 37.40 12.60 0.0 Equil. 85.34 14.32 0.338 88.73 11.10 0.173 160161 80.00 20.0 0.0 84.29 15.71 0.0 Equil. 80.61 18.78 0.612 84.93 14.75 0.318 lfllllill 76.5 23.5 0.0 81.37 18.63 0.0 Equil. 77.35 21.79 0.853 82.25 17.31 0.438 ll'llllill 74.17 25.33 0.0 79.39 20.61 0.0 Equil. 75.23 23.72 1.05 79.87 19.57 0.550 lnlllill 58.07 41.93 0.0 65.0 35.0 0.0 Equil. 61.03 35.99 2.97 68.33 30.03 1.64 1611161 37.88 62.12 0.0 45.0 55.0 0.0 Equil. 45.01 47.86 7.13 53.45 42.37 4.18 161061 24.4 75.6 0.0 30.24 69.77 0.0 Equil. 35.6 53.2 11.2 44.01 44.09 6.84 lnlliiil 23.0 77.0 0.0 28.6 71.4 0.0 Equil. 34.65 53.7 11.65 43.06 49.77 7.15 1611161 14.9 85.1 0.0 19.0 81.0 0.0 Equil. 29.6 55.7 14.7 37.77 52.97 9.26 lnitial 0.0 100.00 0.0 0.0 100.00 0.0 Equil. 21.385 57.23 21.385 28.66 57.19 14.15

7. A pipe according to claim 1 wherein the stabilizer mixture contains 7l to 81% of( l and 29 to 19% of(2) and the amount of trimethyltin compound in the stabilizer is not over 0.6%.

8. A pipe according to claim 2 wherein R is alkyl, cycloalkyl, alkenyl or benzyl.

9. A pipe according to claim 8 wherein R is alkyl of 4 to 12 carbon atoms and n is an integer of l to 2.

10. A pipe according to claim 9 wherein R is alkyl of 8 to l2 carbon atoms.

1 l. A pipe according to claim 10 wherein the LB of the stabilizer is at least 1000.

12. A pipe according to claim 11 wherein the stabilizer is present in an amount of 0.1 to 2.5% by weight of the resin and the resin is a vinyl chloride resin.

13. A composition comprising a halogen containing resin selected from the group consisting of chlorinated polyethylene, a vinyl halide resin and a vinylidene halide resin with a stabilizingly effective amount of a mixture of:

l. 2 to 96% of a compound having the formula:

CH S(CHz)n a CH/ s(cH.).CooR,

and

2. 98 to 4% of a compound having the formula:

having not over 0.6% of a compound having the formula:

CH, cH, n-s(cH, ),.cooR CH, I

as an impurity in the stabilizer and where R; is a hydrocarbon of up to 20 carbon atoms and n is an integer of l to 3.

14. A composition according to claim 13 wherein the stabilizer mixture contains 2 to 60% of (l) and 98 to 40% of (2).

15. A composition according to claim 14 wherein the stabilizer has an LD of at least 695 when administered orally to rats.

16. A composition according to claim 15 wherein R is alkyl, cycloalkyl, alkenyl or benzyl and the LD of the stabilizer is at least 1000.

17. A composition according to claim 16 wherein R; is alkyl of 4 to 12 carbon atoms and n is an integer of l to 2.

18. A composition according to claim 17 wherein R is alkyl of 8 to 12 carbon atoms.

19. A composition according to claim 18 wherein the amount of trimethyltin compound is not over 0.5% of the stabilizer.

20. A composition according to claim 19 wherein the amount of trimethyltin compound is not over 0.4% of the stabilizer.

21. A composition according to claim 14 wherein the stabilizer is present in an amount of 0. l to 5% by weight of the resin.

22. A composition according to claim 21 wherein the stabilizer is present in an amount of 0.l to 2.5% by weight of the resin.

23. A composition according to claim 14 wherein the stabilizer mixture contains 2 to 25% of l) and 98 to of (2) and the amount of trimethyltin compound in the stabilizer is not over 0.6%.

24. A composition according to claim 23 wherein the stabilizer mixture contains 2 to 20% of (l) and 98 to of (2).

25. A composition according to claim 24 containing 20%of( l and 80%of(2) basedonthe total of(l) and (2).

26. A composition according to claim 25 wherein the amount of stabilizer is 2% by weight of the resin.

27. A composition according to claim 26 wherein the resin is polyvinyl chloride.

28. A composition according to claim 24 wherein the stabilizer mixture contains 2 to 20% of (l) and 98 to of (2) and the amount of trimethyltin compound in the stabilizer is not over 0.15%.

29. A composition according to claim 28 wherein the stabilizer mixture contains 2% of (l) and 98% of (2) and not over 0.006% of trimethyltin compound.

30. A composition according to claim 24 wherein R is alkyl, cycloalkyl, alkenyl or benzyl.

31. A composition according to claim 30 wherein R is alkyl of 4 to 12 carbon atoms.

32. A composition according to claim 31 wherein R, is alkyl of 8 to 12 carbon atoms.

33. A composition according to claim 32 wherein the stabilizer is a mixture of dimethyltin bis(isooctylthioglycolate) and methyltin tris (isooctylthioglycolate).

34. A composition according to claim 33 wherein the stabilizer mixture contains 20% of the dimethyltin bis- (isooctylthioglycolate) and 80% of the methyltin tris- (isooctylthioglycolate).

35. A composition according to claim 34 wherein the stabilizer is present in the amount of 2% by weight of the resin.

36. Pipe made of the composition of claim 14.

37. Pipe made of the composition of claim 15.

38. Pipe made of the composition of claim 16.

39. Pipe made of the composition of claim 17.

40. Pipe made of the composition of claim 22.

41. Pipe made of the composition of claim 23.

42. Pipe made of the composition of claim 24.

43. Pipe according to claim 42 wherein the resin is polyvinyl chloride.

44. Pipe according to claim 41 wherein the resin is polyvinyl chloride.

45. Pipe made of the composition of claim 28.

46. Pipe made of the composition of claim 31.

47. Pipe made of the composition of claim 32.

48. Pipe made of the composition of claim 33.

49. Pipe according to claim 47 wherein the resin is polyvinyl chloride. 

1. A PIPE COMPRISING A HALOGEN CONTAINING RESIN SELECTED FROM THE GROUP CONSISTNG OF CHLORINATED POLYETHYLENE A VINYL HALIDE RESIN AND A VINYLIDENE HALIDE RESIN WITH A STABILIZINGLY EFFECTIVE AMOUNT OF A MIXTURE OF (1) 60 TO 96% OF A COMPOUND HAVING THE FORMULA
 2. 4 to 40% of a compound having the formula CH3 - Sn (S(CH2)nC00R3)3 and having not over 0.6% of
 2. 98 to 4% of a compound having the formula: CH3-Sn(S(CH2)nC00R3)3, and having not over 0.6% of a compound having the formula:
 2. A pipe according to claim 1 wherein the stabilizer has an LD50 of at least 695 when administered orally to rats.
 3. A pipe according to claim 2 wherein R3 is alkyl, cycloalkyl, alkenyl or benzyl and the LD50 of the stabilizer is at least
 1000. 4. A pipe according to claim 3 whereiN R3 is alkyl of 4 to 12 carbon atoms and n is an integer of 1 to
 2. 5. A pipe according to claim 4 wherein R3 is alkyl of 8 to 12 carbon atoms.
 6. A pipe according to claim 3 wherein the stabilizer is present in an amount of 0.1 to 5% by weight of the resin.
 7. A pipe according to claim 1 wherein the stabilizer mixture contains 71 to 81% of (1) and 29 to 19% of (2) and the amount of trimethyltin compound in the stabilizer is not over 0.6%.
 8. A pipe according to claim 2 wherein R3 is alkyl, cycloalkyl, alkenyl or benzyl.
 9. A pipe according to claim 8 wherein R3 is alkyl of 4 to 12 carbon atoms and n is an integer of 1 to
 2. 10. A pipe according to claim 9 wherein R3 is alkyl of 8 to 12 carbon atoms.
 11. A pipe according to claim 10 wherein the LD50 of the stabilizer is at least
 1000. 12. A pipe according to claim 11 wherein the stabilizer is present in an amount of 0.1 to 2.5% by weight of the resin and the resin is a vinyl chloride resin.
 13. A composition comprising a halogen containing resin selected from the group consisting of chlorinated polyethylene, a vinyl halide resin and a vinylidene halide resin with a stabilizingly effective amount of a mixture of:
 14. A composition according to claim 13 wherein the stabilizer mixture contains 2 to 60% of (1) and 98 to 40% of (2).
 15. A composition according to claim 14 wherein the stabilizer has an LD50 of at least 695 when administered orally to rats.
 16. A composition according to claim 15 wherein R3 is alkyl, cycloalkyl, alkenyl or benzyl and the LD50 of the stabilizer is at least
 1000. 17. A composition according to claim 16 wherein R3 is alkyl of 4 to 12 carbon atoms and n is an integer of 1 to
 2. 18. A composition according to claim 17 wherein R3 is alkyl of 8 to 12 carbon atoms.
 19. A composition according to claim 18 wherein the amount of trimethyltin compound is not over 0.5% of the stabilizer.
 20. A composition according to claim 19 wherein the amount of trimethyltin compound is not over 0.4% of the stabilizer.
 21. A composition according to claim 14 wherein the stabilizer is present in an amount of 0.1 to 5% by weight of the resin.
 22. A composition according to claim 21 wherein the stabilizer is present in an amount of 0.1 to 2.5% by weight of the resin.
 23. A composition according to claim 14 wherein the stabilizer mixture contains 2 to 25% of (1) and 98 to 75% of (2) and the amount of trimethyltin compound in the stabilizer is not over 0.6%.
 24. A composition according to claim 23 wherein the stabilizer mixture contains 2 to 20% of (1) and 98 to 80% of (2).
 25. A composition according to claim 24 containing 20% of (1) and 80% of (2) based on the total of (1) and (2).
 26. A composition according to claim 25 wherein the amount of stabilizer is 2% by weight of the resin.
 27. A composition according to claim 26 wherein the resin is polyvinyl chloride.
 28. A composition according to claim 24 wherein the stabilizer mixture contains 2 to 20% of (1) and 98 to 90% of (2) and the amount of trimethyltin compound in the stabilizer is not over 0.15%.
 29. A composition according to claim 28 wherein the stabilizer mixture contains 2% of (1) and 98% of (2) and not over 0.006% of trimethyltin compound.
 30. A composition according to claim 24 wherein R3 is alkyl, cycloalkyl, alkenyl or benzyl.
 31. A composition according to claim 30 wherein R3 is alkyl of 4 to 12 carbon atoms.
 32. A composition according to claim 31 wherein R3 is alkyl of 8 to 12 carbon atoms.
 33. A composition according to claim 32 wherein the stabilizer is a mixture of dimethyltin bis(isooctylthioglycolate) and methyltin tris (isooctylthioglycolate).
 34. A composition according to claim 33 wherein the stabilizer mixture contains 20% of the dimethyltin bis(isooctylthioglycolate) and 80% of the methyltin tris(isooctylthioglycolate).
 35. A composition according to claim 34 wherein the stabilizer is present in the amount of 2% by weight of the resin.
 36. Pipe made of the composition of claim
 14. 37. Pipe made of the composition of claim
 15. 38. Pipe made of the composition of claim
 16. 39. Pipe made of the composition of claim
 17. 40. Pipe made of the composition of claim
 22. 41. Pipe made of the composition of claim
 23. 42. Pipe made of the composition of claim
 24. 43. Pipe according to claim 42 wherein the resin is polyvinyl chloride.
 44. Pipe according to claim 41 wherein the resin is polyvinyl chloride.
 45. Pipe made of the composition of claim
 28. 46. Pipe made of the composition of claim
 31. 47. Pipe made of the composition of claim
 32. 48. Pipe made of the composition of claim
 33. 49. Pipe according to claim 47 wherein the resin is polyvinyl chloride. 